I. Field of the Invention
This invention relates to microstrip transmission lines operating in the millimeter wave region of the frequency spectrum and, more particularly, to a transition for providing a low loss, broadband interconnection between a microstrip transmission line dielectric substrate and another microstrip transmission line dielectric substrate.
II. Description of The Prior Art
Microstrip transmission line circuitry is widely used in radar and communications systems and subsystems operating in the millimeter wave region of the frequency spectrum. The use of such planar circuitry in systems and equipment permits the system and low weight. A problem frequently encountered, however, is the connection of one microstrip transmission line substrate to another microstrip transmission line substrate. The connection circuitry or "transition" must not only be of compact design and small size and low weight but must permit the electrical connection to be made without violating the boundary line conditions, e.g., electric field orientation, etc., which are necessary for successful wave propagation at the millimeter wave frequencies. Many of the prior art solutions of the transition problem require that the microstrip transmission dielectric substrate be perforated with a hole or other opening to accommodate the transition element. This adds to the labor costs of fabricating the transition equipment and often requires the use of skilled assembly labor thereby raising the overall costs of the system or equipment in which the transition is used.